The Plain Prinia is a small (15 cm) bird
with grayish brown upperparts, light grayish underparts with yellowish buff
flanks, a yellowish buff supercilium and a long tail. The bill is mostly
yellow, the legs are pink and the iris brown. The Taiwan race
flavirostris differs from adjacent mainland forms in having a yellow
rather than a blackish bill, and a greenish instead of rufous tinge to the
upperparts in winter.

The Plain Prinia feeds mainly on insects
such as caterpillars, ants and small beetles, and also on some flower
nectar. Its song is a long, monotonous insect-like trill sustained for ten
seconds or more and its calls include a rapidly repeated “chip” or “chi-up”
note and a plaintive “tee-tee-tee”.

The Plain Prinia is a common resident of
Taiwan in open grassy areas, reed beds, marshes, paddy fields and cultivated
land from low to mid elevations.

References: A Field Guide to the Birds of China (Mackinnon
and Phillipps); 100 Common Birds of Taiwan (Wild Bird Society of Taipei); N.
J. Collar, “Endemic
subspecies of Taiwan birds—first impressions”, in Birding ASIA, Number 2,
December 2004